Ukranian Prime Minister Mykola Azarov gestures during a session of the Parliament in Kiev. The Ukrainian parliament rejected a motion to hold a vote of confidence in the government on Tuesday, following massive pro-EU protests calling for the resignation of President Viktor Yanukovich and his government.

Ukrainian security forces stormed a tent encampment in central Kiev, converging on Independence Square from three sides to roust sleeping protesters and beat those refusing to clear the streets, witnesses reported.

Blaring through loudspeakers early Wednesday, police ordered the demonstrators demanding the ouster of President Viktor Yanukovich and his government to heed a city court order to end their obstruction of traffic and communications.

Opposition supporters and others outraged by the president's November 21 decision to scrap an agreement that would have improved trade and other relations with the European Union in favour of closer ties with Russia have been occupying the historic centre of the Ukrainian capital for three weeks.

Lawmakers taking part in the protest tried to shield the rest of the crowd of 5000 from the onslaught, linking arms in expectation that the immunity they enjoy as elected officials would be respected by police.

But as the charging security forces knocked down and kicked opposition lawmaker Andrei Pyshny, the crowd shouted "Shame!" and vowed to fight to the end.

Hours earlier, the standoff between the Western-leaning protesters and Yanukovich's Russia-aligned base appeared to pause for diplomatic efforts aimed at ending the country's worst political crisis since the 2004 Orange Revolution.

The four men who have served as Ukraine's presidents since independence held a rare meeting Tuesday in a nationally televised round-table discussion. Yanukovich offered tokens of reconciliation to his political opposition, but nothing that was likely to end the demonstrations.

Ukrainian envoys are going to Brussels on Wednesday to resume negotiations on integration, Yanukovich said as he sat with former Presidents Leonid Kuchma, Leonid Kravchuk and Viktor Yushchenko.

"We want to get conditions that would satisfy Ukraine, Ukrainian producers and Ukrainian people today," Yanukovich said.

"As soon as we reach mutual understanding and compromise, (my) signature will be there."

He also promised to release some of the protesters detained during earlier demonstrations.

Yanukovich also reportedly met Tuesday with EU envoy Catherine Ashton, who was dispatched to Kiev to help seek a solution to the political crisis.

The opposition was not invited to the presidents' meeting, and its leaders dismissed the results.

"It was not a dialogue but a monologue on the part of Yanukovich, who once again didn't say anything the country wanted to hear," opposition lawmaker Natalia Agafonova said in an interview.

"If the president had really wanted a dialogue, he would have met with the opposition and would have come out to the people" in Independence Square.

As night fell, riot police and other security forces, brought by busloads to Kiev from all over Ukraine, dismantled opposition barricades around government buildings and pushed thousands of protesters back to Independence Square.

In a brief clash before the square was swept around 1am, 15 protesters and two policemen were reportedly lightly injured. The Interior Ministry said also that 40 police officers had been sidelined with colds and that two had fainted while on duty.

With snow falling and temperatures dipping into the single digits, the number of protesters had dwindled to several thousand from hundreds of thousands Sunday. Those remaining found warmth where they could.

"Our protesters get warm near fires in Independence Square, they regularly get hot food, tea and coffee during the day, and they are replaced in time by thousands of new protesters, while these young soldiers who face us stay all day out in the snow, wind and cold," Agafonova said.

"Protesters often bring hot tea and snacks to the police, who are frozen and miserable and about to pass out."

In his round-table meeting, Yanukovich once again bemoaned a natural gas agreement with Russia that was signed by former Prime Minister Yulia Tymoshenko. Tymoshenko is serving a seven-year prison term for abuse of power over her decision to sign the deal with Russia in 2009, a conviction her supporters say is politically motivated. One of the EU conditions for signing an integration agreement with Ukraine is that Tymoshenko be freed.

Ukraine can't pay Russia's existing price for gas, which is much higher than the average European price, Yanukovich said.

"Today, Russia is ready to discuss this issue," he said. An EU economic pact would threaten those discussions.